BERLIN: In the heart of Germany’s largest city, fisherman Klaus Hidde wades through the shallow ponds and creeks of Britzer Garten park shortly after dawn to check his 17 traps. The spoils are rich. As he shakes out the nets, hundreds of tumble into his basket.

The 63-year-old, whose family has fished for generations, is the spearhead of Berlin’s new effort to rid its waters of the invasive , putting him in the unlikely position of practising his trade in the middle of the bustling capital.

Crayfish, indigenous to the southern US and , were likely introduced into Berlin’s ecosystem a few years ago after pets were dumped into local rivers, but their population has boomed over the past two years after particularly mild winters.

The invasive animal, known as Louisiana Crayfish, has been crowding out the native ‘Edelkrebs’ crayfish population and has also introduced a fungus, which has been harming the already-endangered German crustacean. Now, Berlin wildlife commissioner Derk Ehlert has granted Hidde an exclusive license to collect as many of the crustaceans as he could and sell them to local restaurants.

Get latest news & live updates on the go on your pc with . Download The for your device. in English and other languages.